1. Technical Field
The invention relates to depth cameras, particularly to a depth camera with a symmetric light source.
2. Related Art
A depth camera can be used to control a computer through a gesture. Moreover, a depth camera can be further used to control a TV game through a body motion. This makes human-machine interaction more intuitive.
Such human-machine interaction needs a depth camera which can store a three-dimensional image into a two-dimensional format. A depth camera can measure a Z-axis distance between every shot point and the camera so that it can record three-dimensional image data.
A common method for measuring the Z-axis distance is to use the principle of time of flight (TOF). Simply speaking, a time period from a light beam emitted by a light source to be reflected by a shot point to come back to the origin can be used to calculate the Z-axis distance.
A key to the TOF principle is creature of the light source. A light source of a typically conventional depth camera is lighting units arranged on only one side of the lens. However, in practice, such an arrangement will cause an apparent and sharp shadow. The shadow will reduce the image quality. Additionally, the light source is provided with shades to isolate the influence of other light sources. A conventional method for assembling the shades is to manually process the shades one by one. Such a method must generate an error which will deflect the light beam from the light source. This will cause a distortion to the position of the shot object. This is a primary drawback of the TOF method.